A neat function I discovered during the challenge is
STRING_AGG which strings together (concatenates) non null string values in a single field.
This was by no means a requirement but instead of the output below, I wanted to return a table that shows the 3 customer id's and for each customer id strings together the different product names in a single cell.
So what's the syntax for creating the output below?
Turns out it's a lot simpler than I thought.
Instead of this ...
SELECT customer_id, product_name FROM q5_items_sold_ranked WHERE count_rank = 1 ORDER BY customer_id ASC;
... do this.
SELECT customer_id, STRING_AGG(product_name, ', ') AS most_popular_items FROM q5_items_sold_ranked WHERE count_rank = 1 GROUP BY customer_id ORDER BY customer_id ASC;
Hope you find this useful, let me know in the comments if any questions.